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AIR FOR COMBUSTION
AND VENTILATION
Continued
If the actual Btu/Hr used is less than the maximum
Btu/Hr the space can support, the space is an uncon-
fined space. You will need no additional fresh air
ventilation.
WARNING: If the area in
which the heater may be oper-
ated is smaller than that defined
as an unconfined space or if the
building is of unusually tight
construction, provide adequate
combustion and ventilation air
by one of the methods described
in the National Fuel Gas Code,
ANSI Z223.1/NFPA 54 Section 5.3
or applicable local codes.
VENTILATION AIR
Ventilation Air From Inside Building
This fresh air would come from an adjoining un-
confined space. When ventilating to an adjoining
unconfined space, you must provide two permanent
openings: one within 12" of the ceiling and one
within 12" of the floor on the wall connecting the
two spaces (see options 1 and 2, Figure 2). You
can also remove door into adjoining room (see
option 3, Figure 2). Follow the National Fuel Gas
Code, ANSI Z223.1/NFPA 54, Section 5.3, Air for
Combustion and Ventilation for required size of
ventilation grills or ducts.
Ventilation
Grills
Into Adjoining
Or
Room,
Remove
Option 1
Door into
Adjoining
Room,
Option
3
Figure 2 - Ventilation Air from Inside
Building
111826-04C
12"
Ventilation Grills
Into Adjoining Room,
Option 2
12"
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Ventilation Air From Outdoors
Provide extra fresh air by using ventilation grills or
ducts. You must provide two permanent openings:
one within 12" of the ceiling and one within 12"
of the floor. Connect these items directly to the
outdoors or spaces open to the outdoors. These
spaces include attics and crawl spaces. Follow the
National Fuel Gas Code, ANSI Z223.1/NFPA 54,
Section 5.3, Air for Combustion and Ventilation for
required size of ventilation grills or ducts.
IMPORTANT: Do not provide openings for inlet
or outlet air into attic if attic has a thermostat-
controlled power vent. Heated air entering the attic
will activate the power vent.
Outlet
Air
Outlet
A ir
Inlet
Air
Inlet Air
Figure 3 - Ventilation Air from Outdoors
Ventilated
Attic
To Attic
To
Crawl
Space
Ventilated
Crawl Space
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